Packer apparatus with latching mechanism



ug 18 1970 H. R. ARMSTRONG 3,524,501' J PACKER APPARATUS WITH LATCHING MECHANISM 3 Sheets-Sheet 1 Filed July 1.5. 1968 FIG. 3

Flejz FIG. i

INVENTOR HAROLD R` ARMSTRONG ATTORNEYE.

u8- i8 1970 H. R. ARMSTRONG 3,524,50

PCKER AFPARATUS WITH LATCHING MECHANISM Filed July 15. 196e s sheets-sheet 2 2:. a f., L\\\ ..lil

f w l A \\\\w/ INVENT OR HAROLD R. ARMSTRNG E ATTORNEYS.

Aug. 18, 1970 Filed July l5. 1968 FIG. 5c

H. R. ARMSTRONG PACKER APPARATUS WITH LATCHING MECHANISM s sheets-sheet s FIG. 5d

INVNTOR HAROLD R, ARMSTRONG ATTORNEY United States Patent O1 3,524,501 Patented Aug. 18, 1970 hee 3,524,501 PACKER APPARATUS WITH LATCHING MECHANISM Harold R. Armstrong, Wichita Falls, Tex., assignor to Halliburton Company, Duncan, Okla., a corporation of Delaware Filed July 15, 1968, Ser. No. 744,819 Int. Cl. E21b 23/00 U.S. Cl. 166--182 8 Claims ABSTRACT OF THE DISCLOSURE An apparatus for releasably latching a well packer in its expanded condition, the apparatus being characterized by a latching device carried internally of the packer and operable in response to reciprocation of a conduit string supporting the packer.

GENERAL BACKGROUND, OBJECTS, AND SUMMARY OF THE INVENTION It is a conventional practice in the well testing art to utilize a testing string disposed within a well bore to evaluate the fluid properties of an isolated subteranean formation. At the outset of one testing technique, the lower end of the string is disposed on the base of the well bore. Thereafter, an upper portion of the string is moved downwardly so as to induce telescoping action between telescoping components of a well packer. This telescoping action induces axial contraction and radial expansion of an elastomeric packing element. Such packer expansion provides a sealing relationship between the testing string and the wall of the well bore, operable to isolate a formation to be tested.

It has been a conventional practice to maintain the packer in its expanded condition by merely maintaining a substantial portion of the weight of the testing string acting downwardly on the telescoping components. With such an arrangement, a reduction in the testing string weight acting on the packer may tend to permit radial contraction of the packer. Such contraction, of course, may cause the packer to lose its sealing relationship with the well bore.

The effective sealing action between the packer of the testing apparatus and the wall of the well bore is essential to the success of a formation testing operation. The packer is expanded to sealingly engage a well bore wall portion so as to isolate a portion of the well bore adjacent the formation to be evaluated. This isolation enables the testing apparatus t be placed in uid communication with the isolated zone, so that physical properties of formation fluids in the isolated zone may be evaluated.

Where the isolation of the Zone to be tested is imperfect, due to a partially contracted packer, the results of the formation testing operation may be inclusive or erroneous. Errors may well arise due to leakage between the isolated zone and other portions of the well bore.

yIt thus is a principal object of the present invention to provide a packer setting apparatus, including a latching mechanism which enables the packer to be releasably and effectively latched in its expanded condition.

It is a further object of the invention to provide such a latching mechanism which is operable in response to simple linear movement of a conduit string within a well bore.

Yet another principal object of the invention is to provide such a latching mechanism which is effectively housed and contained in its latched position so as to provide protection for the latched components.

It is a related object of the invention to provide such a housing system for a packer latching mechanism which provides a holding force directed substantially perpendicular to the direction of forces acting on the latching components and tending to induce their separation.

A still further object of the invention is to provide a latching structure which is characterized by basic simplicity and operaitonal ruggedness, and which may be readily incorporated in conventional packer systems without requiring extensive modification of the packer structures.

In accomplishing at least some of these objectives, there is presented through the invention an apparatus comprising packer means, actuating means, and packer latching means.

The packer latching means is mounted on the interior of the said packer means.

The actuating means includes packer actuating means operable to expand the packer means in response to downward movement of the actuating means Within a Well bore. The actuating means also includes a latch actuating means operable to actuate the latching means in response to downward movement of said actuating means within a well bore. The latch actuating means is operable to releasably secure the packer means in an expanded condition. The latch actuating means is mounted for telescoping movement relative to the packer actuating means. This mounting enables the latch actuating means to move upwardly within a well bore and disable the latching means, prior to upward movement of the packer actuating means which serves to permit contraction of the expanded packer means.

lDRAWINGS FIG. 3 illustrates the components of the FIG. `1`

assembly at a stage where latching mechanism has been disabled so as to permit the contraction of the packer and the withdrawal of the testing string from the Well bore; l FIG. 4 provides a perspective view, in an exploded format, of the components of a latching mechanism supported by a packer mandrel of the FIG. 1 assembly; and F-IGS. 5a, 5b, 5c and 5d provide a partially sectioned, enlarged, and elevational view of the components of the FIG. l assembly, it being understood that these components have been separated for purposes of illustration at the indicated separation lines, cz-a, b-b and c--c.

PRINCIPAL COMPONENTS FIGS. l, 2 and 3 illustrate the principal components of a packer setting and latching apparatus with this apparatus being disposed within a well bore 2.

The general mode of operation of the apparatus 1, apart from the unique latching concept of the present invention, is described in detail in a pending application of Hosea P. Hearn, Ser. No. 694,458, filed Dec. 29, 1967 and assigned to the assignee of the present application. It is sufiicient to here note that the principal components of the apparatus include packer assembly 3, conduit means v4 extending upwardly from packer assembly 3, and conduit means 5 extending downwardly from packer means 3.

Conduit means 4 is operable to support packer assembly 3 and lower conduit means 5, from a well head, not

3 shown, to permit the entire assembly to be lowered into a well bore.

`Conduit means 5, as described in the aforesaid Hearn application, and as is well known in the formation testing art, may include a perforate conduit portion. This perforate portion will provide iiuid communication between the interior of conduit means 5 and an isolated subterranean formation whose iiuid properties are to be evaluated.

Testing apparatus 1 includes an actuating assembly 6 providing an interconnection between conduit string 4 and packer assembly 3.

Actuating assembly 6 includes an outer conduit or packer actuating means 7 operable to cause axial contraction and radial expansion of an elastomeric packer means 8 in packer assembly 3. This expansion of packer means 8 is effected by downward movement of the outer conduit 7, with the lower end of conduit means 5 engaging the base of the well bore 2.

Upward movement of the outer conduit means 7, with conduit means 5 remaining in its iixed position, serves to permit the expanded packer means 8 to relax, i.e., contract radially inwardly.

Actuating means `6 also includes a latch actuating and holding means comprising an inner conduit 9. Inner conduit 9 is telescopingly mounted within outer conduit 7. A spline joint 46 provides an interconnection between the inner conduit 9 and the outer conduit 7. This interconnection permits limited longitudinal movement of conduit 9 relative to conduit 7.

Apparatus 1 additionally includes latching means 10. Latching means 10 includes a female component 11 carried by conduit 7 and a composite male component 12 carried by a mandrel portion 13 of the packer assembly 8.

It will be here understood that the mandrel 13 of packer assembly 3 defines a packer component xedly connected with fixed conduit means 5. Packer means 8 is telescopingly mounted on the exterior of this mandrel 13.

When latching component 12 has been telescopingly inserted into latching component 11, the latched relationship between these telescoped components 11 and 12 is perfected and secured by the insertion of inner circuit conduit 9 into the component 12. Removal of conduit 9 from component 12 permits the separation of latch components 11 and 12.

STRUCTURAL DETAILS OF PACKER ASSEMBLY Packer assembly 3, as shown in FIGS. 1, 2, 3, 5b, 5c and 5d, includes the central and generally cylindrical mandrel 13. A conventional threaded coupling 14 serves to iixedly interconnect the mandrel 13 With the conduit means 5.

Packer means 3 includes lower, packer expansion inducing shoe 15. This shoe 15 is fixedly secured to coupling 14 by a generally cylindrical turnbuckle 16.

The expansible packer means 8 includes a lower, generally cylindrical, elastomeric packer element 18.

Packer elements 17 and 18 are separated by a generally radially extending flange 19. Flange 19 is carried on a generally tubular support 20. Tubular support 20 is interconnected, by a spline joint 21, with mandrel 13 for telescoping movement relative to the interior of the mandrel 13.

A threaded collar 22 is secured to the lower end of spline connection 21, on the exterior of mandrel 13. This collar serves to limit downward movement of the packer support 20.

The upper ends of the packer means 8 is engaged by a packer expansion inducing, shoe 23. Packer shoe 23 is interconnected with packer element 18 through a cylindrical ring 24 embedded in packer lement 18. A plurality of threaded rod fasteners extends from this embedded ring 24 to individual securing apertures 25 in the packer shoe 23.

Packer shoe 23 is interconnected with a generally cylindrical component 26 of conduit means 7 by a generally cylindrical, internally threaded turnbuckle 27. Relative rotation between the components 26 and 23 may be irnpeded by an intermeshed tooth structure 28, described in detail in the aforesaid Hearn application. It is suflicient to here note that this saw tooth structure comprises a first series of circumferentially spaced, downwardly facing triangularly cross-sectioned teeth carried by the lower end of compent 26. A second series of upwardlly facing, similarly constructed saw teeth is carried by the upper end of the component 23 and meshingly engages the iirst series.

`One or more O-rings 29 may be provided to alford sealing engagement between the relatively telescoping components 26 and 13. The O-rings 29 may be secured in place, in a notch-like recess 30 formed in the interior of component 26, by securing sleeve 31.

As illustrated in FIG. 5c, securing sleeve 31 may be attached to the interior of packer shoe 23 by a series of circumferentially spaced spring lingers 32. These spring lingers comprise integral, downward projections of a sleeve body 33. Each of the lingers 32 is provided with a detent 34. Each such detent 34 is operable to latchingly engage a generally annular recess 35 formedon the interior of the packer shoe 23.

It will now be apparent that downward movement of the component 26, with conduit means 5 resting on the base of the well bore, will cause the shoe 23 to move downwardly toward the generally -lixed shoe 15. This convergence of shoe 23 and 15 will induce axial contraction and radial expansion of the packer elements 17 and 18.

In this connection it will be noted that the sleeve 20 is operable to move downwardly on mandrel 13 to an extent sufcient to permit the axial contraction and radial expansion of the packer element 17.

DETAILS OF ACTUATING MEANS Structural details of actuating means 6 are illustrated in FIGS. 1, 2, 3, 5a and 5b.

Actuating means 6, as previously noted, includes outer conduit means 7 and inner conduit means 9.

Outer conduit means 7 may comprise threadably interconnected components 36, 37 and 26.

A spline joint 38 permits limited telescoping movement between the conduit means 7 and the packer mandrel 13. As shown in FIG. 5b, spline joint 38 comprises a plurality of circumferentially spaced lugs 39. These lugs 39 project radially outwardly from mandrel 13 into longitudinally extending slots 40 formed on the interior of component 26. Axial travel of components 26 is limited by longitudinally spaced, annular abutments 41 and 42. Abutments 41 and 42 engage the upper end and lower end of the lugs 39 respectively, at the points of lowermost and uppermost movement of the conduit means 7 relative to the packer mandrel 13.

Inner conduit means 9 comprises a generally cylindrical component 43 and an upper component 44. Component 44 is threadably connected to the lower end of conduit means 4 by coupling 4a.

Components 43 and 44 are threadably interconnected. Conduit means 9 may be provided, on its exterior, with an annular seal 45'. This seal 45 is operable to provide slidable and sealing engagement between the conduit means `6 and the component 36 of outer conduit means 7.

A spline joint 46 provides for limited telescoping movement of conduit means 9 relative to conduit means 7.

Spline joint 46 comprises a longitudinally extending lug 47 which projects radially outwardly from the exterior of component 44. This lug provides a spline connection between conduit means 9 and a removable cylindrical cap 48 threadably secured to the upper end of component 36.

The lug 47 is slidably received in a longitudinally extending slot 49 facing member 48. This slot 49 faces radially inwardly as shown in FIG. 5a. Spline joint means 46 is provided with one or more lugs 50 which serve to limit the extent of upward reciprocating movement of the conduit means 9 relative to the conduit means 7.

The manner in which the lugs 50 serve to permit but control this telescoping movement is described in detail 1n U.S. Barrington et al. Pat. No. 3,368,829.

In brief, it should be noted that the lugs 50 are operable to reciprocate between an annular ledge 51 facing upwardly and formed in a lower portion of component l36 and another ledge, 48a, defined by member 48, and facing downwardly. Engagement of lugs 50 with ledge 48a prevents means 6 from moving upwardly out of engagement with outer conduit means 7.

As described in the aforesaid Barrington et al. patent, a series of circumferentially spaced but axially staggered barriers 52 are provided in the interior of the component 36. These barriers, i.e. splines, permit the lugs 50r to be rotated through limited, circumferentially staggered, increments at opposite ends of the interior component 36. This enables an operator to raise the conduit means 9, rotate the conduit means 9 through a fixed increment so as to partially unscrew the cap 48 from the component '36, lower the conduit means 9 and further rotate conduit means 9 to cause further unscrewing of the components 48 and 36, and continue this process until complete separation of the components 48 and 36 is achieved.

Thus, the lugs 50' and the spline-like barriers 52 cooperate to provide a safety-joint connection in the manner described in the aforesaid Barrington et al. patent.

As shown in FIGS. 5a and 5b, the component 43 is provided with an open lower end 53 and a plurality of radially extending, perforations or passages 54.

STRUCTURAL DETAILS OF LATCHING MECHANISM Structural details of latching mechanism are shown in FIGS. 1, 2, 3, 4 and 5b.

Latching mechanism 10` includes a generally cylindrical housing 55 defined by the lower end of component 37. Housing 55 is generally cylindrical in nature and provides a central passage 56 having an open lower end 56a. The inner wall of component 55, defining the passage 56, is provided with a female threaded recess or surface 57. This surface 57 extends longitudinally of the apparatus 1 and the passage 56.

Composite latching component 12, as shown in FIGS. 4 and 5b, includes a contractible mandrel 58, a contractible detent 59, and a positioning or abutment defining collar 60.

Contractible mandrel 58 includes a generally cylindrical base portion 61. This base portion mounts a longitudinally extending lug 62 which projects radially outwardly of the exterior of base portion 61. A threaded coupling 63 serves to connect the mandrel 58 with the packer mandrel 13.

Mandrel 58 is provided with a plurality of circumferentially spaced and longitudinally extending spring fingers 64. These resilient fingers 64 project upwardly from the mandrel body 61 and define integral extensions of body 61.

Each spring finger 64 is provided with a radially outwardly enlarged upper end 65. Each enlarged upper end 65 provides a generally downwardly facing cam surface 66. Each cam surface 66 is inclined generally upwardly and outwardly with reference to the central longitudinal axis of the assembly 1 and the mandrel 58.

Each enlargement 65 also includes an upwardly facing guide surface 67. Each such guide surface 67 is inclined upwardly and outwardly with respect to the central axis of the mandrel 58.

As will be apparent with reference to FIG. 5b and FIG. 4, the Camming surfaces 66 of the various spring fingers 64 cooperate to yield a generally frustoconically configured, downwardly facing, cam surface 68 interrupted lby the spaces 69 between adjacent fingers 64.

Similarly, the guide surfaces 67 of the spring fingers 64 cooperate to define a generally, frustoconically configured, upwardly facing guide surface 70. Guide surface 70 is circumferentially interrupted by the spaces 69 between the fingers 64.

Contractible detent 59 comprises a cylindrical segment 71, circumferentially interrupted by a longitudinally extending gap or slot 72.

Segment 71 carries on its exterior, a longitudinally extending, circumferentially interrupted, male threaded surface 73.

With detent S9 in its relaxed condition, surface 73 is operable to threadingly, i.e., matingly engage thc recess means defined by the threaded surface 57.

Abutment defining collar 60 comprises a cylindrical body 74. A slot or recess 75 extends longitudinally of the interior of cylindrical body 74.

The components 58, 59 and 60 are assembled with mandrel 13 as shown in FIG. 5b. This assembly is effected yby telescoping the detent 59 over the lower end of the mandrel 58, with the slot 72 permitting the detent body 71 to by-pass the lug 62.

The sleeve-like collar 60 is then telescopingly assembled over the lower end of the mandrel 59 to secure the detent 59 in position. The telescoping of component 60 over component 59 is permitted by the slot 74 slidably receiving the lug 62.

The slot 75 cooperates with the lug `62 to provide a spline joint connection 76. This spline joint connection 76 enables a wrench or other tool to be applied to the tool engageable exterior surface 77 of component 60. In this manner, torque may be transmitted to the coupling 63 and threadably connect the mandrel 58 with the packer mandrel 13. It should be here noted that this threadable connection is effected without applying torque to the spring fingers 64.

With the components assembled, the collar 60A rest on an abutment 78 defined by the upper end of mandrel 13. The upper end 79 of collar 60I provides an annular abutment operable to support the detent 59, with the upper end 80 of detent 59 spaced somewhat beneath the cam means 69, i.e., out of Camming engagement with this cam means.

The upper end 80 of detent 59 is provided with a frustoconical camming surface 81. Camming surface 81 is inclined upwardly and outwardly with reference to the central axis of the detent 59. As illustrated, Camming surface 81 may be configured to be generally conformingly engageable with the cam means 68.

MODE OF OPERATION OF ASSEMBLY With the components disposed as shown in FIG. 1

and FIGS. Sa-Sd, the inner conduit means 9 has been moved downwardly to its lower-most position relative to conduit means 7. This movement extremity is defined by engagement of a downwardly facing, frustoconical sur face 82 of component 44 with an upwardly facing, frustoconical surface 83 formed on the interor of component 36.

With this disposition of components, downward force applied to the conduit means 4 will induce concurrent downward movement of the conduit means 9' and 7.

At the outset of this concurrent downward movement, downward movement of the packer s'hoe 23 will be initiated to commence expansion of the packer elements 18 and 17 As downward movement of the conduit means 4 is continued, the mandrel fingers 64, and the surface 73 of detent 59, will telescopingly enter the passage 56. Because of the contractible nature of the detent 59, the surface 73 will ratchet upwardly within the surface 58. This ratcheting is permitted because of the contractible nature of the detent 59 and an annular gap 84 which exists between the detent body 71 and the fingers 64.

While the fingers 64 and detent 59 are entering the recess 56, the tubular component 43 is entering the open upper end 85 of the central passage 86 of the contractible mandrel 58. The entry of the lower end 53 of component 43 into the passage 86 is facilitated by the guide surface means 70.

The outer wall 87 of component 43 is diametered so as to matingly and telescopingly engage the radially interior surfaces 88 of the fingers 64, when these fingers are disposed in their relaxed condition.

Downward movement of the conduit means 4 is continued until the desired packer expansion is achieved. The extent f expansion will determine where the detent surface 73 will be positioned longitudinally within the recessed surface 57.

The interlatched disposition of the latch components, with the packer expanded, is shown in FIG. 2.

With the latch components thus interengaged, the surface 87 exerts a latch holding force, directed perpendicularly or radially outwardly with reference to the central axial of the assembly. This holding force is thus directed perpendicular to the longitudinal separation forces acting between the conduit means 7 and the packer mandrel 13. This separation force, which is caused by the tendency of the packer elements 17 and 18 to radially contract and axially expand, will tend to move the surface 57 upwardly and thus carry the detent 59 upwardly. Upward movement of the detent 59 will cause the cam surface 81 to cammingly engage the cam surface means 68. Camming cooperation between the surface means 81 and 68 will serve to prevent contraction of the detent 59. With detent contraction thus prevented, relative movement between the conduit means 7 and the mandrel 13 will be prevented. Thus, the packer 8 will be effectively latched in its expanded condition.

The camming action or surface means 68 will remain effective so long as the surface 87 prevents radially inwardly directed exing of the upper ends of the spring fingers 64.

Thus, in order to release the latch components from their latched relationship shown in FIG. 2, it is merely necessary to raise the conduit means 4 so as to move the inner conduit means 6 upwardly to an extent sufficient to withdraw the component 43 from the passage 86. This movement of conduit means 6 may be effected without moving conduit means 7 due to the travel of spline joint 46.

With the component 43 thus withdrawn from detent 58, the spring finger ends 65 are free to flex inwardly so as to permit contraction of the detent 59. Under this condition, the conduit means 7 is free to move upwardly, with the surface 57 ratcheting over the contractible detent 59.

This upward movement of the conduit means 7 may be induced by the contracting forces of the packer elements 17 and 18 and/or by the raising of the conduit means 4 to an extent suicient to cause the conduit means 9 to abutingly engage conduit means 7. This engagement, effected by lugs 50 engaging surface 48u, will permit upward movement of conduit means 4 to cause upward movement of the conduit means 7.

FIG. 3 illustrates the apparatus components with the member 43 withdrawn from the latch component 12, and with the conduit means 6 raised to its limit of uppermost movement relative to the conduit means 7. Continued upper movement of the conduit means 4 will raise the conduit means 7 and ensure radial contraction of the expanded packer means 8. With the packer means 8 contracted, further upward movement of the conduit means 4 will serve to withdraw the apparatus 1 from the well bore 2.

SUMMARY OF ADVANTAGES AND SCOPE OF THE INVENTION A principal advantage of the invention resides in the manner in which the latching mechanism effectively actuates and houses latch components in response to a simple linear movement of a conduit string.

Another major advantage of the invention resides in the ability of the latching mechanism to latch a packer through a range of expanded conditions. Since the detent is able to latchingly engage the latching recess, whether the packer is partially or fully expanded, and since the inner conduit is able to perfect and maintain the latched condition of the detent and recess whether the packer is partially or fully expanded, the latching mechanism is characterized by a broad operational range.

The perforate conduit, latch actuating means provides a housing member operable to prevent a pressure buildup wtihin the latch housing as defined by the conduit 9 and the housing 37.

The abutment defining collar 60 provides a unique mechanism for supporting the detent and facilitating the assembly of the latching components. With this collar, assembly of the components may be effected without applying wrenching forces to the mandrel fingers `64. The collar 60, as illustrated, provides a wrenching surface 77 which extends longitudinally, along at least a portion of the fingers 64, so as to shield these fingers while a wrench is being applied to the wrenching surface 77.

The holding action of the surface 87 is directed radially outwardly, i.e., generally perpendicular to the longitudinal forces tending to induce contraction of the packer elements 17 and 18. Thus, the latch holding forces are applied in a direction where they are least vulnerable to the inuence of the unlatching forces. Such unlatching forces may be imposed by the tendency of the packer elements to contract, or by upward movement of the conduit means 4 which would tendto permit packer contraction.

The combination of the packer structure, actuating means, and safety joint means provides a uniquely effective but structurally simple well tool latching mechanism including a latch actuating component which may be selectively disengaged from the entire assembly. By appropriately manipulating the safety joint, the inner conduit 9 may be fully withdrawn from the conduit 7 so as to leave the expanded packer in the well bore, latched in place, and amenable to subsequent retrieval.

In describing the invention, reference has been made to a preferred embodiment. However, those skilled in the formation testing art and familiar with the disclosure of this invention may Well envision additions, deletions, substitutions or other modifications which would fall within the purview of the invention as defined in the appended claims.

I claim.

1. A formation testing apparatus comprising:

packer means:

actuating means;

said actuating means including,

packer actuating means operable to expand said packer means in response to downward movement of said actuating means within a well bore;

packer latching means mounted on the interior of said packer actuating means;

said actuating means further including,

latch actuating means operable to telescope within said packer latching means to actuate said latching means in response to downward movement of said actuating means within said well bore;

said latch actuating means being operable to secure through said packer latching means said packer means in an expanded condition; and

said latch actuating means being mounted for telescoping movement realtive to Said packer actuating means, to enable said latch actuating means to move upwardly within said well bore above and spaced from said packer latching means and disable said packer latching means prior to upward movement of said packer actuating means which serves to permit contraction of said expanded packer means.

2. A well apparatus comprising: well tool means; actuating means; said actuating means including, t

tool actuating means operable to actuate said tool means in response to linear movement of said actuating means within a well bore; tool latching means mounted on the interior of said well actuating means; said actuating means further including,

latch actuating means operable to telescope within said tool latching means to actuate said latching means in response to linear movement of said actuating means within said well bore; said latch actuating means being operable to secure said well tool means in one condition; and said latch actuating means being mounted for telescoping movement relative to said tool actuating means to enable said latch actuating means to move linearly within said well bore above and sapced from said tool latching means and disable said latching means prior to linear movement of said tool actuating means which serves to permit said well tool means to be released from said one condition. 3. A retrievable formation testing apparatus comprising:

a packer assembly including radially expansible packer means; latching means operable to releasably lock said packer means in an expanded condition, said latching means including recess means, detent means, detent support means, said detent means being supported by said detent support means and operable to engage said recess means to secure said packer means in an expanded position, means carried by said detent support means and operable to prevent disengagement of said detent means from said recess means; actuating means including packer setting means operable to induce expansion of said packer means, and latch actuating means operable to telescope within said detent support means and prevent disengagement of said detent means from said recess means. 4. A retrievable formation testing apparatus comprising:

a packer assembly including generally cylindrical packer mandrel means, generally cylindrical, axially contractible, and radially expansible packer means telescopingly mounted on the exterior of said packer mandrel means, first packer shoe means lixedly positioned on the exterior of said packer mandrel means and engaging a lower end of said packer means when said apparatus is disposed in a bore hole, and second packer shoe means mounted for telescoping movement on the exterior of said packer mandrel means and engageable with an upper end of said packer means when said apparatus is disposed in a well bore, said second packer shoe means being operable to move toward said irst packer shoe means and induce axial contraction and radial expansion of said packer means; latching means operable to releasably latch said packer means in said radially expanded condition, said latching means including generally cylindrical housing means, housing passage means extending generally longitudinally of said housing means and having an open end facing downwardly when said apparatus is disposed in a well bore, recess means formed in said housing means and extending generally radially outwardly of said housing passage means, radially contractible detent means, radially contractible and generally cylindrical mandrel means, said contractible detent means being telescopingly supported on the exterior of said contractible mandrel means, cam means carried by said contractible mandrel means and operable in response to upward movement of said detent means in said well bore, realtive to said contractible mandrel means to prevent radial contraction of said detent means, and abutment means spaced below said cam means when said apparatus is disposed in a well bore and operable to support said detent means out of camming engagement with said cam means, said contractible mandrel means having an open contractible end adapted to face upwardly when said apparatus is disposed within a well bore, said contractible mandrel means and said detent means being operable to telescopingly enter said housing passage means and dispose said detent means in releasable latching engagement with said recess means; conduit means including an outer conduit, telescopingly mounted on the exterior of said packer mandrel means and operable to induce downward movement of said second packer shoe means toward said rst packer shoe means by moving downwardly in a well bore while said packer mandrel means is xed in position within said well bore, and an inner conduit operable to telescopingly enter said open end of said contractible mandrel means and prevent radial contraction of said contractible mandrel means and said detent means which would be operable to disengage said detent means from latching engagement with said recess means, said inner conduct being adapted to be connected with a conduit string extending upwardly from said inner conduit to a well head of said well bore; first spline joint means interposed between said outer iconduit and said packer mandrel means, said first spline joint means being operable to permit limited telescoping movement between said outer conduit and said packer mandrel means longitudinally of a well bore but prevent axial separation of said outer conduit and said packer mandrel means; second spling joint means interposed between said inner conduit and said outer conduit and operable to permit limited telescoping movement between said inner conduit and outer conduit longitudinally of said well bore but prevent axial separation of said inner conduit and outer conduit; safety joint means operable to permit selective disengagement of said inner and outer conduit means; said contractible mandrel means of said latch means including threaded connecting means operable to connect said contractible mandrel means with the mandrel means of said packer means with the open contractible end of said contractible mandrel means facing upwardly within said well bore, cylindrical body means, and spline lug means extending longitudinally of the outer periphery of said body means; said abutment means of said latch means including 1 1 a collar telescopingly mounted on the exterior of said contractible mandrel means, slot means extending longitudinally of said collar and receiving said spline lug means so as to provide a third spline joint means between said collar and said contractible mandrel means operable to permit telescoping movement of said collar relative to said contractible mandrel means, and tool engageable surface means carried by said collar and operable to transmit coupling force through said collar to said threaded connecting means without transmitting force through said open contractible end of said contractible mandrel means; and connecting means attaching said housing means of said latching means to said outer conduit of said conduit means, with said housing means being disposed in coaxial relation with said contractible mandrel means, and with said open contractible end of said mandrel means and said detent means mounted on said contractible mandrel means being operable to telescopingly enter said housing passage means; downward movement of said conduit means in a Well bore being operable to cause said outer conduit to induce downward movement of said second packer shoe means, with said downward movement of said second packer shoe means causing axial contraction and radial expansion of said packer means, said housing means of said latching means to move telescopingly over said open contractible end of said contractible mandrel means to cause said open contractible end of said contractible mandrel means and said detent means to telescopingly enter said hosuing passage means and position said detent means in latching engagement with said recess means, and said inner conduit to be telecopingly inserted into said open contractible end of said contractible mandrel means and engage said open contractible end of said contractible mandrel means so as to prevent contraction of said contractible mandrel means and said detent means operable to free said detent means from latching engagement with said recess means; said latching engagement of said detent means with said recess means being operable to prevent upward movement of said second packer shoe means relative to said packer mandrel means; said cam means of said latching means being operable to cammingly engage said detent means, in response to upward movement of said detent means relative to said contractible mandrel means caused by upward movement of said recess means, with said camming engagement between said cam means and said detent means being operable to prevent radial contraction of said detent means out of said latching engagement with said recess means; and upward movement of a conduit string connected with said inner conduit being operable to move said inner conduit out of engagement with said contractible mandrel means to permit contraction of said contractible mandrel means and said detent means in response to upward movement of said housing means and outer conduit, With said `contraction permitting said detent means to disengage from said latching engagement with said recess means;

said second spline means enabling upward movement of said inner conduit, subsequent to said disengagement of said detent means from latching engagement with said recess means, to induce upward movement of said outer conduit operable to permit axial extension and radial contraction of said packer means.

5. An apparatus as described in claim 4, wherein: said recess means includes a female threaded surface extending longitudinally of said housing passage means;

said contractible detent means includes a generally cylindrical segment,

a slot extending longitudinally of said segment to permit circumferential and radio1 contraction of said segment, and

a male threaded surface for-med on and projecting outwardly from the exterior of said cylindrical segmentand adapted to matingly engage said female threaded surface formed in said housing passage means; and

said contractible mandrel means includes a plurality of longitudinally extending and circumferentially spaced latching fingers,

a camming surface carried at the upper end of each latching finger, when said apparatus is disposed in a well bore, each said camming surface being inclined upwardly and outwardly of the central axis of said contractible mandrel means when said apparatus is disposed in a well bore, and

a guide surface carried at the upper end of each finger when said apparatus is disposed in a well bore, each said guide surface facing generally upwardly and being inclined upwardly and outwardly of said central axis, when said apparatus is disposed in a well bore,

said camming surfaces of said latching fingers dening said cam means of said latching means, with said cam means providing a generally frustoconical cam configuration interrupted by circumferential spacing between the said latching fingers,

said guide surfaces of said latching fingers providing a generally frustoconical guide surface means interrupted by said circumferential spacing between said latching fingers and operable to guide the entry of said inner conduit into the contractible open end of said contractible mandrel means,

said inner conduit, when inserted into said contractible open end of said contractible mandrel means, being operable to abuttingly engage said latching fingers to prevent radially inward movement of said latching fingers.

6. A well apparatus comprising: a well tool; latching means operable to releasably lock said well tool in one condition, said latching means including recess means,

detent means,

detent support means,

said detent means being supported by said detent support means and operable to engage said recess means to secure said well tool means in said one condition,

means carried by said detent support means and operable to prevent disengagement of said detent means from said recess means,

actuating means including well tool operating means operable to place said well tool in said one condition, and

latch actuating means operable to telescope within said detent support means and prevent disengagement of said detent means from said recess means.

13 7. A well tool latching apparatus comprising: latching means operable to releasably latch a well tool in a particular condition, said latching means includlng generally cylindrical housing means, housing passage means extending generally longitudinally of said housing means and having an open end facing downwardly when said apparatus is disposed in a well bore, recess means formed in said housing means and extending generally radially outwardly of said housing passage means, radially contractible detent means, radially contractible and generally cylindrical mandrel means, said contractible detent means being telescopingly supported on the exterior of said contractible mandrel means; cam means carried by said contractible mandrel means and operable in response to upward movement of said detent means in said Well bore, relative to said contractible mandrel means, to prevent radial contraction of said detent means, and abutment means spaced below said cam means when said apparatus is disposed in a Well bore and operable to support said detent means out of camming engagement with said cam means, said contractible mandrel means having an open contractible end adapted to face upwardly when said apparatus is disposed within a well bore, said contractible mandrel means and said detent means being operable to telescopingly enter said housing passage means and dispose said detent means in releasable latching engagement with said recess means; and actuating means including a conduit operable to telescopingly enter said open end of said contractible mandrel means and prevent radial contraction of said contractible mandrel means and said detent means which would be operable to disengage said detent means from latching engagement with said recess means, said conduit being adapted to be connected with a conduit string extending upwardly from said inner conduit to a well head of said well bore; said contractible mandrel means of said latching means including cylindrical body means, and spline lug means extending longitudinally of the outer periphery of said body means; and said abutment means of said latching means including a collar telescopingly mounted on the exterior of said contractible mandrel means, slot means extending longitudinally of said collar and receiving said spline lug means so as to provide spline joint means Ibetween said collar and said contractible mandrel means operable to permit telescoping movement of said collar relative to said contractible mandrel means, and tool engageable surface means carried by said collar and operable to transmit coupling force through said collar to said threaded connecting means without transmitting force through said open contractible end of said contractible mandrel means.

8. An apparatus as described in claim 7, wherein:

said recess means includes a female threaded surface extending longitudinally of said housing passage means;

said contractible detent means includes a generally cylindrical segment,

a slot extending longitudinally of said segment to permit circumferential and radial contraction of said segment, and

a male threaded surface formed on and projecting outwardly from the exterior of said cylindrical segment and adapted to matingly engage said female threaded surface formed in said housing passage means; and

said contractible mandrel means includes a plurality of longitudinally extending and circumferentially spaced latching fingers,

a camming surface carried at the upper end of each latching nger, when said apparatus is disposed in a well bore, each said camming surface being inclined upwardly and outwardly of the central axis of said contractible mandrel means when said apparatus is disposed in a Well bore, and

a guide surface carried at the upper end of each finger when said apparatus is disposed in a well bore, each said guide surface facing generally upwardly and being inclined upwardly and outwardly of said central axis, when said apparatus is disposed in a well bore,

said camming surfaces of said latching fingers defining said cam means of said latching means, with said cam means providing a generally frustoconical cam configuration interrupted by circumferential spacing between the said latching fingers,

said guide surfaces of said latching fingers providing a generally frustoconical guide surface means interrupted by said circumferential spacing between said latching fingers and operable to guide the entry of said conduit into the contractible open end of said contractible mandrel means,

said conduit, when inserted into said contractible open end of said contractible mandrel means, being operable to abuttingly engage said latching lingers to prevent radially inward movement of said latching fingers.

References Cited UNITED STATES PATENTS 1,672,169 6/1928 Putnam 166-182 3,011,558 12/1961 Conrad 166--217 3,311,171 3/1967 Castro 166-196 3,433,304 3/ 1969 Pavlas 166-139 JAMES A. LEPPINK, Primary Examiner U.S. Cl. X.R. 

